London - Arsene Wenger expects Arsenal midfielder Aaron Ramsey to be out of action for up to a month with a thigh injury as the Gunners continue their bid for a domestic double.
The FA Cup holders, bidding to lift the trophy for a third straight season, face Watford in the quarter-finals at the Emirates on Sunday, with Wenger's side eight points behind Premier League leaders Leicester.
Wales international Ramsey limped off during Tuesday's FA Cup fifth-round replay win at Hull, having spent just 16 minutes on the field at the KC Stadium after coming off the bench to replace Gabriel.
Arsenal manager Wenger, asked on Friday if Ramsey would be ruled out for the rest of the season, replied: "I don't believe that.
"At the moment his clinical signs are quite positive. I would say four weeks. It was a bit worse than I thought because I didn't see it," the veteran French boss added.
"Usually when a player gets injured with a muscle, he stops and I did not have that feeling of precaution so I thought he would be available for Sunday."
North London side Arsenal are now entering a defining period of their season, with the Watford match coming before they travel to Barcelona with the difficult task of overturning a 2-0 first leg deficit against the Champions League holders.
Upon their return from Spain, Arsenal travel to Everton and could kick-off at Goodison Park up to 11 points adrift of Leicester.
But for Wenger it remains a matter of just taking one game at a time.
"We want to stay alive in all of them (competitions) but then again let's be focused on the next one," he said.
"I don't believe anyone in my side is thinking about Barcelona at the moment, or Everton, they are completely focused on Watford."